|Publication number||US7345243 B2|
|Application number||US 11/304,867|
|Publication date||Mar 18, 2008|
|Filing date||Dec 15, 2005|
|Priority date||Dec 17, 2004|
|Also published as||CN101080787A, CN101080787B, EP1831899A1, US7655866, US8253023, US9029706, US20060162949, US20080142246, US20100101826, US20120318558, WO2006066232A1|
|Publication number||11304867, 304867, US 7345243 B2, US 7345243B2, US-B2-7345243, US7345243 B2, US7345243B2|
|Inventors||Masud Bolouri-Saransar, Michael V. Doorhy, David R. Hawkins, Asef Nimer Baddar, Thomas Gerard McLaughlin|
|Original Assignee||Panduit Corp.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (32), Referenced by (5), Classifications (7), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims the benefit of U.S. Provisional Application No. 60/637,239, filed Dec. 17, 2004 and entitled “Communication Cable with Variable Lay Length,” which is also incorporated herein by reference in its entirety.
The present invention is generally directed to communication cables and more specifically directed to communication cables having variable lay lengths.
Communication cables comprised of multiple twisted pairs of conductors are common, with four-pair cables being widely used. In a four-pair cable, the twisted pairs of conductors may in turn be twisted around a central axis of the cable. The length of cable in which one complete twist of the twisted pairs is completed around the cable's central axis is considered the “core lay length” of the cable. For example, if the twisted pairs complete one rotation around the central axis of the cable every six inches, the core lay length of the resulting cable is six inches.
A communication channel may comprise a communication cable with connectors at the ends of the cable. Suppression of crosstalk in and between communication channels is important, because crosstalk can reduce the signal-to-noise ratio in a channel and increase the channel's bit error rate. Power-sum alien near-end crosstalk (“PSANEXT”) between channels can be caused by common-mode noise introduced into the channels at connectors. This common mode noise is relative to one conductor pair within a channel, and the common mode noise has its greatest impact when adjacent cables have identical core lay lengths. As communication bandwidth increases, the reduction of crosstalk between channels becomes increasingly important.
According to one embodiment of the present invention, an improved communication cable has core lay lengths that vary along the length of the cable.
According to some embodiments of the present invention, segments of the cable are provided with approximately uniform core lay lengths along the segment lengths, and core lay lengths of the cable vary by a factor of two among neighboring segments of the cable.
The transition length within the cable from one core lay length to a different neighboring core lay length may be kept short to help reduce PSANEXT between adjacent channels.
Multiple core lay lengths may be used along a length of cable.
The lengths of cable segments with different core lay lengths may be kept approximately periodic. Jitter may be introduced into the periodicity to reduce the likelihood of adjacent lengths of cable having identical core lay lengths when cables are installed alongside one another.
In high-bandwidth communication applications, communication cables are commonly installed alongside one another and PSANEXT can result between adjacent or nearby communication cables. PSANEXT between communication cables is greatest when the adjacent communication cables—or adjacent segments of communication cables—have identical core lay lengths. Thus, to decrease PSANEXT it is desirable to minimize the likelihood of adjacent communication cables—or cable segments—having identical core lay lengths. Further, PSANEXT is effectively canceled out if the core lay lengths of adjacent cables or adjacent cable segments differ by a factor of two. Thus, to further decrease PSANEXT it is desirable to maximize the likelihood of adjacent communication cables—or cable segments—having core lay lengths that differ by a factor of two.
A cable may be provided with a core lay length that varies along the length of the cable.
The differences in the core lay lengths are illustrated in an exaggerated fashion by the wave illustration 11 of the core lay lengths of
Transition regions 15 are provided between segments 16 of the cable 10 having the first core lay length and segments 18 of the cable 10 having the second core lay length. The benefits of aligning segments having the first and second core lay lengths are not present along the transition regions 15, and thus it is desirable for the lengths of the transition regions 15 to be small in relation to the length of the cable. According to one embodiment, the transition regions 15 have lengths of from about 5 to about 15 feet. According to another embodiment, the transition regions 15 have lengths equal to or less than approximately ten feet, or equal to or less than approximately 18% of a length of cable. Other transition lengths may be available, depending on the capabilities of the cable manufacturing process.
As shown in
In the alignment shown in
Turning now to
Cables according to the present invention may be manufactured with a variety of values for the nominal segment lengths, “x/2”, as shown in
Because the magnitude and sign of the jitter distance z may change along the length of the cable, segments 28 having the first core lay length may vary in length from one to the next, as may segments 30 having the second core lay length in some embodiments. A graphical diagram of a portion of a resulting cable is shown in
In the cable 32 shown in
Turning now to
According to some embodiments of the present invention, the ratio of core lay lengths of neighboring segments of a cable is 2:1 or a whole number multiple of 2:1. According to other embodiments of the present invention, multiple core lay lengths are used, with a ratio of 1:2:4 among three contiguous neighboring segments. According to another embodiment of the present invention, a ratio of 1:2:4:8 is preserved among four contiguous neighboring segments. According to another embodiment of the present invention, additional core lay lengths may be used, as long as the relationship between the core lay lengths of neighboring segments of the cable is a factor of 2.
In an alternative embodiment, neighboring core lay length segments do not necessarily need to have core lay lengths that differ by a factor of two. For example, a cable 44 as illustrated in
In cables according to embodiments of the present invention, the core lay length of the cable in a segment remains fixed throughout that segment before making a transition to the next core lay length. Cables may be provided with a core lay length pattern that repeats itself, and according to one embodiment the core lay length pattern repeats itself approximately every 1000 feet after initial values of the jitter distance z have been selected substantially randomly. According to some embodiments, the core lay length repeats itself from approximately every 500 to approximately every 1500 feet. According to other embodiments, the jitter distance between cable segments is continuously randomly adjusted during cable manufacture, and cables according to such embodiments will have no period over which any alternating cable lay length pattern necessarily repeats itself.
Cables according to the present invention that incorporate jitter distances into the periodicity of the core lay lengths are capable of reducing PSANEXT noise at frequencies greater than 300 MHz by approximately ten decibels.
According to one embodiment of the present invention, a cable is marked on the exterior of the cable jacket to identify the location and ratio of each core lay length to facilitate optimum installation of each cable.
While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7655866 *||Feb 2, 2010||Panduit Corp.||Communication cable with variable lay length|
|US8253023||Aug 28, 2012||Panduit Corp.||Communication cable with variable lay length|
|US9029706||Aug 24, 2012||May 12, 2015||Panduit Corp.||Communication cable with variable lay length|
|US20080142246 *||Feb 28, 2008||Jun 19, 2008||Panduit Corp.||Communication Cable With Variable Lay Length|
|US20100101826 *||Jan 13, 2010||Apr 29, 2010||Panduit Corp.||Communication Cable with Variable Lay Length|
|Cooperative Classification||Y10T29/49117, H01B11/04, H01B13/04|
|European Classification||H01B13/04, H01B11/04|
|Mar 29, 2006||AS||Assignment|
Owner name: PANDUIT CORP., ILLINOIS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BOLOURI-SARANSAR,MASUD;DOORHY, MICHAEL V.;HAWKINS, DAVIDR.;REEL/FRAME:017405/0542;SIGNING DATES FROM 20060215 TO 20060216
Owner name: GENERAL CABLE TECHNOLOGY CORPORATION, KENTUCKY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BADDAR, ASEF NIMER;MCLAUGHLIN, THOMAS GERARD;REEL/FRAME:017405/0538
Effective date: 20060327
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